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    <title>ShellCheck: SC2172 – Trapping signals by number is not well defined. Prefer signal names.</title>
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    <h1>SC2172 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC2172">See this page on GitHub</a>
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    <h2
id="trapping-signals-by-number-is-not-well-defined-prefer-signal-names">Trapping
signals by number is not well defined. Prefer signal names.</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC2172.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="bu">trap</span> myfunc 28</span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC2172.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="bu">trap</span> myfunc WINCH</span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>Signal numbers can vary between platforms. Prefer signal names, which
are fixed.</p>
<p>Signal numbers 1, 2, 3, 6, 9, 14 and 15 are specified as parts of the
optional POSIX XSI and ShellCheck will not warn about these.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>None.</p>
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